Several factors have pushed Micro-Space communications system development to the “front burner”. Recent postings have analyzed lunar communications. But the other side of the equation always involves what hardware we have working. Analysis of the SETI Institute capabilities helps define “what we Don't need to invent”. The High Definition wideband video can be sent in less than ½ hour with that receiver facility. The problem remains of how we will communicate with our spacecraft for the days – and possible weeks – of each mission. Employing the massive SETI array for “housekeeping” operations is neither cost effective nor necessary.

I mentioned earlier that 1000 Watts of RF power would be required to communicate the high definition video (10 mega bit/sec) to a one meter square receiving antenna. Using the one meter receiving antenna, this collapses to 1 Watt if the data rate is reduced to a healthy 9600 Baud, and to 30 milliwatts for still adequate 300 Baud telemetry data. The RF requirement for the control uplink is similar. The low power numbers permit the antennas on the Lander and Rover to be further simplified.

Back to the “What we have working” question: the control and telemetry links we have been producing and using with our Liquid Fuel rockets do not have the performance required for direct communication to the Moon. They are more than adequate for satellite use, including in CubeSats. The downlink is the easier problem, for we have operated with RF signals as low at 10 nanovolts with our low noise receiver. A modest transmitter in a satellite at synchronous orbit (23,000 miles) would work very well with this receiver. We have recently perfected microcontroller based data encoding and decoding systems which will sustain this communication reliably with very low signal levels. But the lowest signal levels are possible only with synchronous detection and preferably with a fully coherent communications circuit. We are working towards that goal, and have pulled a number of relevant subsystems from past projects into that effort.

The hardware mass situation is much more satisfying. Our rockets used a 3.9 gram mass transmitter, a 10.7 gram receiver and a 2.9 gram telemetry package. This 17.5 gram combination was the core of our 1.3 inch diameter, guided “Storm Probe”. With a cardboard body and less than 1 pound mass, this was an FAA “Exempt” - “Model Rocket” - and could be flown legally in many places.

Our “Storm Probe” had sufficient range to be guided into a selected region of a tornado by a “Storm Chaser” team. The interferometric position tracking and the coherent range data would provide a high resolution map of the Probe's position in three dimensional space, second by second, and record this overlaid onto real time video imagery. At a selected time, the rocket Probe would deploy a descent streamer, and travel with the storm winds. Unlike hypothetical “Passive” storm probes, these (multiples could be launched and simultaneously tracked) would have a high probably of entering the storm and do so at a selected altitude and azimuth.

This is just one of our “Products” which never found interested users – typical of the “Technology Driven” company. But it does provide us with the technology to produce very low mass spacecraft systems. We do need to add a low noise amplifier to the receiver. While this has a potential mass far below one gram, it does add interesting development and testing issues. At present it does not look like the coherent operating mode needs to add any mass at all, but only if our microcontroller takes over some signal processing functions. Under 25 grams for the RF control link systems looks achievable.

We are preparing to hook this system up and start logging “miles” on our rover. I will report these results as they happen.